"We love this movie, we love your city, and having the two of them together will show the cities of the world in a light that it hasn't been shown, certainly not in America," Whedon told the city of Seoul last week. "For us to showcase it in the manner we're going to, and to have all the exciting action as part of 'Avengers: Age of Ultron,' is a real privilege. I apologize for how hard it is to do. But in the end, it's something special, so thank you."

"Age of Ultron" hits theaters on May 1, 2015, with a cast that also includes Robert Downey Jr. as Iron Man, Mark Ruffalo as Hulk, Chris Hemsworth as Thor, Scarlett Johansson as Black Widow and James Spader as Ultron.